Down hole hydraulic pump for formation testing



Nov.v 11, 1958 P. WILLIAMS 2,859,828

DowN 'HOLE HYDRAULIC PUMP FOR FORMATION TESTING Filed De@ 14. 1955 2sheets-snee; 1

lNvENToR PHILIP S. WILLIAMS BY 14m/7% ATTORNEY Noxvr. 11, 1958 y P. s.`WILLIAMS 2,859,828

D OWN HOLE HYDRAULIC PUMP FOR FORMATION TESTING lmit lowering of thehydrostaticpi'essure United States Patent DOWN HoLE HYDRAULIC PUMP rouronM-ArroN rust-mo Philip S. Williams, rIulsa, Okla., assignor, by mesneassignments, to Jersey Production Research Company Application December14.,` 1953,Seriu No. 398.010 4; Claims. (er. 16a- 187) This invention isconcerned with the sampling of'uids from a well bore employed inexploration for and' productionof petroleum from the earth. Theinvention is concernedA with a hydraulic pump of a` character which canbe suspended within a Welly bore for operation by circulation ofdrilling mudthrough the bore hole. The mud pump arrangement disclosedherein is adapted for usage with any type of formation tester topermitobtaining the full benefits of formation testing procedures. whileat'the same time providing certain unique features.

In drilling a bore hole during. exploration for oil deposits in theearth, it is essential at various stages inthe operation to test thenature of fluids present in the bore hole to determine when oil, gas, orwater deposits have been encountered during drilling. The problem ofsampling fluids from a bore hole is complicated by the fact thatdrilling mud is conventionally used in the bore hole to maintain a highhydrostatiepressure during drilling. Consequently, in arder te sampleuds present in a bere hole, it is necessary to mahe provision forl atleast locally sealing olf a portion of the bore hole to be sampled'l forfluid production so as to exclude drilling mud and to perin this. locaLportionV so that fluid canbe produced. Formation testing apparatus isemployed for this general purpose.` Formation testersv of a widevarietyl are employed, but one of the most attractive forms of suchdevices is the inflatable packer type. Inflatable packer formationtesters are provided with an elastic packer arrangement which can beused to seal oif a portion of the bore hole so as to exclude drillingmud and so asl tov permit decreasing the hydrostatic pressure at thesealedI portion of the bore hole. channels for fluid how must beprovided from. the sealed portion ofthe bore hole to. a suitable samplechamber or to a huid passage extending to the surface of the earth.

While the general requisites of formation testing have long beenappreciated and while many desirable types of formation testers havebeen suggested, the need still exists for improving formation testingpractices in several ways'. For one thing, it is a `problem to suitablyreduce hydrostatic pressure adjacent a formation to be tested so as topermit the recovery of fluids which may be present at low formationpressures.` This problem is particularly serious in the case of certaintight producing z ones Where the presence of oil may easily beoverlooked by conventional techniques. For example, in order toreducehydrostatic pressure at a stratum to be sampled, it has beensuggested that a vacuum pump may be employed at the surface of the earthto lower hydrostatic pressure in a drill string or conduit in tluidcommunication with the formation to be tested;` This technique, however,is seriously limited; by the fact that a pressure differential can onlybe developed equivalent to a head of about thirty feet of water. lttherefore becomes; desirable to develop a suitable forrn of force pumpwhich maybe located down the hole `adjacent the formation to be testedso, that the pumping limitation referred to`v can be avoided. It is oneobject of this invention to provide an attractive form of Suitable vfwlce 2 hydraulic force pump` for this purpose in which circulation ofdrilling mud in the bore hole is used to secure the pumping action.

Other particular problems associated with formation testing which havenot been fully solved concern the retention of clean uncontaminatedsamples of fluid produced during testing, the problem of determiningwhen testing has proceeded far enough so that testingl can beterminated, and the problem of permitting repetition of formationtesting at different levels in-the bore hole without necessity forretrievingY the apparatus from the bore hole. The present inventionaccomplishes each of these purposes in providing a novel and attractiveform of hydraulic pump assembly forl use in combination with any desiredtype of formation tester.

In order to describe a preferred embodiment of the invention, theinvention will be described with particular reference to the type offormation tester disclosed and claimed in U. S. Patent 2,600,173, issuedto Ben W. Sewell et al. on June 10, 1952'. The formation testeridentified in this patent; is of the elastic packer type suspended on adrill string to be used within a bore hole and normally employing thecirculation. of drilling mud through the drill string in order tocontrol inflation and deflation of the packer. The present invention isparticularly attractive foruse in combination with this type offormation tester. In fully `describing the nature of this invention,reference will be made to the accompanying drawings, in which:

Figure 1- diagra'mmatically' illustrates in cross-sectional, elevationaldetail the upper portion of the hydraulic pump assembly;

Figure 2 is a lower continuation of the apparatus of Figurel terminatingat its lower portion in a formation tester of the nature described inPatent No. 2,600,173.;

Figure 3 is a cross-sectional, elevational detail drawing of analternative form of the invention using a different type of hydraulicpump assembly than thatl shown in Figure 2;

Figure 4 illustrates the u se of a sample chamber in combination withthe apparatus of Figures 1 and 2 and essentially illustrates the sameportion of the apparatus` illustrated `in Figure 1 with a suitablesample chamber in operative position in the apparatus, and;

Figure 5 is a lower continuation of the apparatus of Figure 1 utilizinga formation tester similar to the one described in Patent No. 2,600,173.

Referring first to Figures 1 and 2, the basic features of the hydraulicpump assembly of this invention can be appreciated. In these figures itis` assumed that the pump assembly is supported in a bore hole by meansof a drill string or tubular support member 2 which may be integrallyconnected with the pump assembly sub or body `3 having the same externaldiameter as the drill string 24 and supporting at the lower portion aninflatable packer formation tester 4. In the apparatus of Figures 1 and2 drilling mud forced downwardly through the drill string 2 from thesurface of the earth enters a channel 5 which passes downwardly to ahydraulic motor 6. Drilling mud passing through channel 5 flows throughthe hydraulic motor 6 so as to exhaust through the nozzle 7. This nozzletogether with intake passage 18 constitutes a jet pump as hereafterdescribed. The hydraulic motor is directly coupled through shaft 8 to apump 9. ln the particular apparatus illustrated in Figures 1 and 2 it isassumed that the hydraulic motor is of the turbine type while. the pump9 may constitute a simple impeller type pump. The intake of pump 9 isconnected through a conduit 10 to the bore hole annulus `so thatdrillingmud willl bepulled Y packer 4 in the manner more particularlydescribed in Patent 2,600,173. While pump 9 may be so constructed andoperated as to provide the desired ination pressure for the packer 4, itis generally desirable to employ a pressure limiting arrangement toprevent possibility for rupturing the elastic packer. Such a pressurelimiting arrangement is illustrated by conduit 12 connecting to conduit11 and opening into the annulus of the bore hole through the check valve13. The retaining spring on check valve 13 is selected so that whensuitable inflation pressure is provided through conduit 11 to theiniatable packer, drilling mud will simply exhaust to the bore holethrough the check valve 13. Y

The inflatable packer is illustrated in Figure and is more fullyexplained in Patent No. 2,600,173. The inatable packer of the formationtester may consist of any suitable form of fiexible, non-porousmembrane. The lower end of the packer is sealingly afiixed to the base55, and the upper end is sealingly aiiixed at 58 to the lower portion ofsub 3. An inner steel mandrel 50 extends through the inflatable packerwith a passage 51 extending through the mandrel. The lower end of thepassage 51 is in open communication with the borehole and the upper endcommunicates with outlet port 56. This provision has the effect ofequalizing the hydraulic pressure acting on the elastic packer so thatno pressure will exist to force the packer either upwardly or downwardlyin the borehole.

The tubing 15 positioned within the packer 4 connects at its lowerportion to the iiuid producing inlets of the formation tester. Thefluid-producing inlets comprise a recess or trough 52 formed in the wallof the packer in communication with tubing 15 and in operation normallypositioned opposite formation 54 to be tested. Recess 52 is packed withinterconnected packing elements 53 held in place by a supporting wire57. Alterations of the formation of these inlets may be found in PatentNo. 2,600,173. Thus fluid produced from a stratum adjacent the bore holewill pass into the formation tester upwardly through tube 15. A checkvalve 16 is positioned in this fluid passage to prevent possibility fordrilling mud to pass in the opposite line of ow downwardly into theformation testing line. For reasons which will later become clear, tube15 is connected to a uid channel 17 so as to connect to a second channel18 through a slide valve arrangement 19. Slide valve 19 may be ofconventional character provided with suitable seals 20 so as to slidablyoperate within the central portion of the assembly sub 3. As illustratedin Figure l, slide valve 19 is normally biased in the open position bymeans of spring 21 so as to permit fluid flow from conduit 17 intoconduit 18. A ycheck valve 22 is positioned in conduit 18 so that fluidflow will be permitted from the slide valve and through the check valve,but so that uid flow will be prevented in the opposite direction.Conduit 18 terminates in a cavity within pump assembly sub 3 adjacentthe nozzle 7. This cavity, identified by numeral 25, opens outwardlyinto the bore hole annulus through a suitable port or ports 26.

With this description of the elements of the apparatus i illustrated inFigures l and 2, one way in which this apparatus can be used can now beunderstood. The apparatus, assembled on a drill string 2, will belowered into the bore hole without the circulation of drilling mudthrough the bore of the drill string. Consequently, during the loweringoperation, the mud pump 9 will not be in operation and the elasticpacker will remain in the deflated condition. When the assembly has beenlowered to the selected position in the bore hole, drilling mud will beforced into the drill string 2 at the surface of the earth. Circulationof the drilling mud through the hydraulic motor 6 will activate the mudpump 9 so as to inflate the elastic packer 4 as described. At the sametime, exhaust of the circulating drilling mud from motor 6 throughlnozzle 7 will create an aspirating effect within the cavity 25 servingto pull fluid from fluid producing conduit 15 through conduits 17 and18. This uid will pass outwardly from cavity 25 and port 26 into thebore hole annulus.

In using the invention in this manner, the pressure drop throughhydraulic motor 6 is kept as low as possible consistent with providingsuitable inflation pressure for the packer by operation of the pump 9.Since relatively low inflation pressures can b e used, essentially thefull mud circulation pressure is available for exerting an aspiratingeffect at the nozzle 7. The apparatus described therefore functionsefficiently for dropping the hydrostatic pressure at the stratumcontacted by the formation tester so as to produce uid from this stratumas described. In the apparatus illustrated in Figures l and 2, theproduced fluid is simply Vexhausted into the bore hole annulus asdescribed and the nature of the uid may be determined at the surface ofthe earth by mud logging 0r other means of detection. Consequently, inthis use of the invention, operation of the apparatus is continued untilsuitable results are obtained by inspection of the iiuid in the borehole annulus at the surface of the earth. When the test has beencompleted, by discontinuing the circulation of drilling mud into thedrill string 2, operation of the hydraulic motor 6 is stopped andelastic packer 4 will be deflated. Thereafter the assembly may be movedto a different level in the bore hole for additional formation tests.

The apparatus described in Figures 1 and 2 essentially utilizes a jetpump action effective by exhaust of drilling mud through the nozzle 7 toproduce fluid from a formation to be tested. The apparatus is readilyadaptable to use of other pumping techniques for producing the testedfluid. Figure 3 illustrates one alternative form of pump arrangement inwhich a hydraulic pump is substituted for the jet pump arrangement ofFigure 2. In Figure 3 elements of the apparatus which are analogous tothose of Figure 2 are identified by similar numerals (using the primenotation to identify elements having a similar function) and attentionwill be directed to those portions of the apparatus which are differentfrom the apparatus of Figure 2.

In the apparatus of Figure 3, drilling mud circulated through the drillstring 2 and channel 5 is passed through the hydraulic motor 6, which isexhausted through a conduit 11y connecting to the inflation conduit ofthe elastic packer 4. As described in connection with Figure 2, conduit11 is bypassed to the bore hole annulus through a conduit12' and checkvalve 13. In this case the hydraulic motor uses the full pumpingpressure of the drilling mud through the drill string with onlysufficient pressure remaining to provide the necessary inflationpressure. Again, the hydraulic motor is directly coupled to a pump 9which may be of the impeller type. The intake of pump 9 is connected toconduit 18' formerly described and the outlet of the pump 9 is connectedto the bore hole annu lus through a conduit 32. It will be apparent thatthe formation uid produced through the formation tester follows the sameuid path described in connection with Figures 1 and 2. However, theapparatus of Figure 3 provides the advantage that greater pumpingpressure is available to produce formation fluid and to exhaust this uidto the bore hole annulus.

It is a particular feature of both embodiments of the inventiondescribed that these pumping assemblies may be used in connection with asuitable sample chamber of the nature illustrated in Figure 4. Forclarity the description of Figure 4 is to be read with Figure l in orderto see the operative relationship of the sample chamber with the pumpassembly. The sample chamber of Figure 4 constitutes an elongatedcylindrical body 33 terminating at its upper portion in a Spearhead 34which may be used to lower and retrieve the sample chamber by means of awire line. The sample chamber 33 is constructed to have an externalconfiguration so that the sample chamber will t within the pump assemblybody 3 but so that a lower section of the sample chamber provided withashoulder 39 will ft within and contact the slide valve 19.Consequently, when the sample chamber is lowered into position, slidevalve 19 will be moved from lthe position illustrated in Figure 1downwardly to the position illustrated in Figure 4. The sample chamberwill be of sufficient mass so as to compress spring 21 for this purpose.

The lower elongated portion of the sample chamber 33 is provided with acheck valve arrangement 35. Check valve 35 may constitute a simple balltype check valve in which the ball is fixed to rod member 36 adapted tocontact the bottom of the sample chamber recess within the pump assemblybody 3 when the sample chamber is in the position illustrated in Figure4. Consequently, check valve 35 will be forced to the open position whenthe sample chamber is in place.

Operation of the pump assembly will be just as dcscribed in connectionwith Figures l, 2, and 3. However, formation fluid produced throughconduit 17, by actuation of slide valve 19, will now follow a coursesuch that the formation fluid will pass into and through sample chamber33. Thus, as illustrated, formation fluid passing upwardly throughchannel 17 will enter a port 37 connecting to a standpipe arrangement 38within the cavity of sample chamber 33. The fluid will pass upwardlythrough standpipe 38 and downwardly about standpipe 38, so as tothoroughly flush the sample chamber, with the fluid finding an exitthrough check valve 35 and the lower termination of the sample chamber.A fluid passage 41 is provided in the body 3 ofthe assembly so that theformation uid will flow back through slide valve 19 and through conduit18 for exit to the bore hole annulus as formerly described.

In using the apparatus of Figure 4, formation fluid will be circulatedthrough the sample chamber in this manner until there is assurance thatthe sample chamber is completely flushed with flowing formation fluid.Thus, circulation can be continued until this condition is indicated bymud logging at the surface of the earth or until operation has continuedso long that it is certain that all `contaminating fluids have beenwashed through the sample chamber. Thereafter the sample chamber isretrieved by a wireline attached to the Spearhead 34 so that the samplemay be brought to the surface of the earth. Lifting the sample chamberwill cause check valve 35 to close and check valve 43 in the inlet tothe sample chamber will similarly close, trapping the uncontaminatedformation fluid within the sample chamber for inspection at the surfaceof the earth.

The invention described is subject to many modifications and refinementsillustrated in the drawings but which have not heretofore beendescribed. For example, to prevent any possibility of drilling mudcontaminating the formation fluid brought into sample chamber 33 ofFigure 4, a cup seal 45 may be positioned about the sample chamber in amanner to exclude any flow of drilling mud about the sample chamber tothe inlet port 37 of the sample chamber. A lower cup seal 46 maysimilarly be used to prevent formation uid from bypassing the samplechamber, ensuring the circulation of all produced formation fluidthrough the sample chamber as described. It should also be noted thatcheck valve 22 in suction line 18 leading to the pump assembly, asillustrated in Figure l, provides the important function of preventingthe possibility of drilling mud backing up into the sample chamber inthe event pumping is stopped before the sample chamber is removed fromthe position shown in Figure 4.

What is claimed is:

l. A formation tester comprising in combination: a tubular supportextending downwardly into a bore hole when in use, an inflatable packerfixed to the lower end portion of said support, a first conduitextending from the exterior surface of the packer through the inflatablepacker to the interior of said support, a second conduit extending fromthe interior of said support through a cavity in said support to theexterior surface of said support, a pump supported by said support, aninfiation conduit means extending from the exterior of said supportthrough said pump to the interior of said packer, a hydraulic motorsupported by said support and adapted for driving said pump, an inletconduit extending from the bore of said support to said motor, anexhaust conduit extending from said motor through a jet nozzle to saidcavity operative to produce an aspirating effect at said nozzle to forcea stream of fluid inwardly through said first and second conduits whendriving fluid is passing through said motor. y

2. The formation tester defined by claim 1 including a pressure reliefmeans in fluid communication with the inflatable packer.

3. The formation tester defined by claim 1 in which check valves arepositioned in both the first and second conduits preventing fluid flowfrom the bore hole annulus back through these conduits.

4. The formation tester defined by claim l including a chamberinsertable in the fluid path through said first and second conduits,said chamber including valved entrance and exit openings for passage offluid through the chamber adapted to retain fluid in the chamber whenwithdrawn from said fluid path.

References Cited' in the le of this patent UNITED STATES PATENTS2,290,141 Burt `uly 14, 1942 2,511,759 Williams June 13, 1950 2,549,728Villines Apr. 17, 1951 2,600,173 Sewell et al 1 June l0, 1952 2,675,080Williams Apr. 13, 1954

